Pressure sensors are currently used in various industries such as automotive, refrigeration, industrial, and agriculture. The main purpose of a pressure sensor is to measure pressure and to provide an electrical output. However, for many uses, it is important that the pressure sensor is compatible with the media in which it is used. A media compatible pressure sensor, sometimes referred to as a media isolated pressure sensor, may be required to work in harsh environments. For example, a media compatible pressure sensor may be used to measure brake fluid in a car. The area which touches the media needs to be inert to the media such as brake fluid, otherwise, the brake fluid may eat away at the material.
At times, the environment can be worse than the media in which the pressure sensor operates. For instance, a pressure sensor device may be located underneath a car which is continually exposed to salt and road dirt. Thus, it is critical to have the packaging for the pressure sensor to be able to withstand both the harsh environment and the media. Typically, many packages for pressure sensors include steel bodies which have laser welding and various other operations performed upon it to achieve the necessary durability. Because of the packaging costs, the conventional pressure sensor device is typically very expensive, ranging from $50-$500.
Another factor which adds to the cost of the conventional pressure sensor device is the inability to automatize the manufacture and testing of these devices due to conventional uses of batch mode processing.
The conventional pressure sensor device also utilizes various flex circuits to provide the necessary interconnects, sending of the output, and signal positioning. The use of flex circuits is typically very expensive and will also add additional interconnects which can perpetuate reliability problems.
Other factors which can create reliability problems include the use of epoxies to glue various components together. Additionally, various portions of the conventional pressure sensor device are typically soldered together which can also create reliability problems.
What is needed is a reliable, inexpensive pressure sensor device which avoids these problems. The present invention addresses such a need.